Mind boggling card trick: Difference between revisions
→{{header|Haskell}}: (Some tidying of the threeStack function, refreshed sample output)
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(→{{header|Haskell}}: (Some tidying of the threeStack function, refreshed sample output)) |
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]
return ns
-- RED vs BLACK ----------------------------------------
rb :: Int -> Char
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-- THREE STACKS ----------------------------------------
threeStacks :: String -> (String, String, String)
threeStacks
where
go tpl [] = tpl
go (rs, bs, ds)
go (rs, bs, ds) (x:
| 'R' == x = go (y : rs, bs, x : ds) xs
| otherwise = go (rs, y : bs, x : ds) xs
-- SHUFFLE -----------------------------------------------
-- (See Knuth Shuffle task)
knuthShuffle :: [a] -> IO [a]
knuthShuffle xs = (foldr swapElems xs . zip [1 ..]) <$> randoms (length xs)
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in a ++ c : drop 1 b</lang>
{{Out}}
<pre>Discarded:
Swapped:
Red pile:
Black pile:
True</pre>
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